diff --git a/libcxx/include/__algorithm/three_way_comp_ref_type.h b/libcxx/include/__algorithm/three_way_comp_ref_type.h
--- a/libcxx/include/__algorithm/three_way_comp_ref_type.h
+++ b/libcxx/include/__algorithm/three_way_comp_ref_type.h
@@ -27,6 +27,13 @@
   _Comp& __comp_;
   _LIBCPP_HIDE_FROM_ABI constexpr __debug_three_way_comp(_Comp& __c) : __comp_(__c) {}
 
+  template <class _Tp, class _Up>
+  _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(const _Tp& __x, const _Up& __y) {
+    auto __r = __comp_(__x, __y);
+    __do_compare_assert(0, __y, __x, __r);
+    return __r;
+  }
+
   template <class _Tp, class _Up>
   _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp& __x, _Up& __y) {
     auto __r = __comp_(__x, __y);
@@ -55,7 +62,7 @@
 
 // Pass the comparator by lvalue reference. Or in debug mode, using a
 // debugging wrapper that stores a reference.
-#  ifndef _LIBCPP_ENABLE_DEBUG_MODE
+#  ifdef _LIBCPP_ENABLE_DEBUG_MODE
 template <class _Comp>
 using __three_way_comp_ref_type = __debug_three_way_comp<_Comp>;
 #  else
diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.three.way/lexicographical_compare_three_way_comp.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.three.way/lexicographical_compare_three_way_comp.pass.cpp
--- a/libcxx/test/std/algorithms/alg.sorting/alg.three.way/lexicographical_compare_three_way_comp.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.sorting/alg.three.way/lexicographical_compare_three_way_comp.pass.cpp
@@ -16,15 +16,15 @@
 //                                       Cmp comp)
 //       -> decltype(comp(*b1, *b2));
 
-#include <array>
 #include <algorithm>
+#include <array>
 #include <cassert>
 #include <compare>
 #include <concepts>
 #include <limits>
 
-#include "test_macros.h"
 #include "test_iterators.h"
+#include "test_macros.h"
 
 using std::array;
 
@@ -161,7 +161,11 @@
 constexpr bool test() {
   test_iterator_types();
   test_comparison_categories();
+  // In debug mode the comparator will be called twice by the debugging wrapper
+  // `__debug_three_way_comp`
+#ifndef _LIBCPP_ENABLE_DEBUG_MODE
   test_comparator_invocation_count();
+#endif
 
   return true;
 }